It is known in the art that tetrahydrofuran can be produced by a number of different methods, the more prominent among them the dehydration of 1,4-butanediol and the catalytic hydrogenation of furan. Most tetrahydrofuran is, in fact, manufactured in a multi-step sequence starting with the reaction of acetylene and formaldehyde in the presence of a cuprous acetylide complex to form butynediol. The butynediol is hydrogenated to butanediol, which is dehydrated to tetrahydrofuran as indicated above. As disclosed in copending applications of William E. Smith Ser. Nos. 623,904 and 623,905, filed on Oct. 20, 1975, both titled A Process for Preparing Tetrahydrofuran and assigned to the same assignee as the present invention and now U.S. Pat. Nos. 4,011,244 and 4,010,171 respectively, tetrahydrofuran can also be produced by dehydroacyloxylation of carboxylate esters of 1,4-butanediol.
In addition, tetrahydrofuran can be prepared by catalytic hydrogenation of maleic, fumaric and succinic acids, their respective anhydrides and ester derivatives, and butyrolactone.
Methods for effecting the dehydration of 1,4-butanediol to tetrahydrofuran previously disclosed include the use of alumina and phosphoric acid catalysts (U.S. Pat. No. 2,251,835), and silica-alumina catalysts (Japanese Patent 73 01 075).
Tetrahydrofuran is a useful solvent for natural and synthetic resins and is a valuable intermediate in manufacture of a number of chemicals and plastics.